What about giving the fighter the exclusive ability to use and specialise in various fighting styles. I never saw anything done with in this direction with 3.5 Perhaps something like this...
Fighting Style Mastery
The fighter chooses one fighting style from among the following list: one weapon, two-handed, two weapons, weapon & shield. Whenever the fighter uses his chosen fighting style, he gains a +1 com-petence bonus to attack rolls, weapon damage rolls and AC. This talent can be gained multiple times. Each time, the fighter takes this talent, he chooses a new fighting style or increases the bonus of one of his existing fighting styles by +1.
Or make it "more complicated" and assign special benefits to different fighting styles.